553
FXUS65 KBYZ 230654
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
1254 AM MDT SAT MAY 23 2026
KEY MESSAGES
- WARMING TREND AND MOSTLY DRY THROUGH MEMORIAL DAY; EXPECT
MOUNTAIN SNOW MELT TO INCREASE RIVER FLOWS.
- INCREASING POTENTIAL FOR SHOWERS AND THUNDERSTORMS BY MIDDLE OF
NEXT WEEK; DETAILS UNCERTAIN AT THIS TIME, BUT SEVERE STORMS AND
HEAVY RAIN ARE POSSIBLE.
DISCUSSION
THROUGH NEXT FRIDAY...
A FINAL WEAK SHORTWAVE IN NW FLOW ALOFT WILL BRING POTENTIAL FOR
A FEW BENIGN SHOWERS/SPRINKLES EARLY THIS MORNING IN OUR WEST, AND
OVER MORE OF THE REGION THIS AFTERNOON. OTHERWISE EXPECT RISING
HEIGHTS AND WARMER TEMPS TODAY, WITH HIGHS IN THE 70S. THERE MAY
ALSO BE A BIT OF EARLY MORNING FOG NEAR THE DAKOTAS BORDER, BUT
BETTER CHANCES WILL BE TO OUR EAST.
SUNDAY & MONDAY WILL SEE A BUILDING RIDGE AND FLOW BACKING TO THE
SW AHEAD OF THE NEXT TROF DIGGING ALONG THE PACIFIC COAST. A SURGE
OF WARMER AIR WILL PUSH TEMPS TO THE 80S SUNDAY AND MID 80S TO
AROUND 90F MONDAY. THERE MAY BE ENOUGH MID LEVEL MOISTURE FROM THE
GREAT BASIN TO PRODUCE WEAK DIURNAL CONVECTION OVER OUR SOUTHERN
MOUNTAINS SUNDAY, BUT THE GREATER POTENTIAL FOR T-STORMS WILL
BEGIN MONDAY OVER THE WEST, PER THE APPROACHING LOW. ANY STORMS ON
MONDAY WOULD BE HIGH-BASED AND PRODUCE GUSTY SURFACE WINDS. ALSO,
THE WARMER TEMPS WILL CAUSE MOUNTAIN SNOW MELT WHICH WILL INCREASE
FLOWS ON RIVERS AND STREAMS...HEADS UP TO THOSE RECREATING OVER
THE MEMORIAL DAY WEEKEND.
POTENTIALLY MORE IMPACTFUL WEATHER BEGINS TUESDAY AS THE PACIFIC
LOW MOVES INLAND. CONFIDENCE IS BUILDING THAT: (1) A CUT OFF LOW
WILL EVOLVE SLOWLY OVER THE GREAT BASIN AS AN OMEGA BLOCK SETS UP
OVER THE CENTRAL CONUS; AND (2) SE-S FLOW WILL PROVIDE MOISTURE
ADVECTION UP THE HIGH PLAINS, WITH ENSEMBLES SHOWING PWATS NEAR AN
INCH FOR MULTIPLE DAYS. GIVEN ALL OF THIS, THOUGH DETAILS REMAIN
UNCERTAIN, WE ARE LOOKING AT A STRING OF DAYS (TUE-FRI) WITH A
CHANCE OF SHOWERS AND T-STORMS, SOME OF WHICH WOULD PRODUCE HEAVY
RAIN. CANNOT STRESS ENOUGH THAT ATMOSPHERIC MOISTURE WILL BE MUCH
HIGHER THAN WE HAVE SEEN SO FAR THIS SPRING. FURTHERMORE, WE COULD
BE LOOKING AT MULTIPLE DAYS WITH A RISK OF SEVERE T-STORMS.
TODAY'S CLUSTER ANALYSES HAVE COME INTO MUCH BETTER AGREEMENT
REGARDING THE POSITIONS OF THE UPPER LOW AND BLOCK TO OUR EAST.
TEMPERATURE-WISE, TUESDAY MAY STILL BE HOT, AS THE ONSET OF
COOLING WILL DEPEND ON THE SPEED WITH WHICH THE LOW MOVES INLAND
AND PRODUCES SHOWERS. WEDNESDAY THRU FRIDAY SHOULD SEE COOLING
WITH MORE CLOUD COVER AND SHOWERS OVERALL (TEMPS BACK TO THE
70S?). ENSEMBLE CONSENSUS IS FOR THE LOW TO LIFT NORTHWARD THRU
WY/ID/MT BY FRIDAY.
ONE FINAL NOTE. IF THE LOW'S POSITION BECOMES FAVORABLE FOR HEAVY
RAIN SHOWERS OVER A PERIOD OF A FEW DAYS, WE'D BE LOOKING AT RAIN
ON SNOW AT HIGH ELEVATIONS AND ENHANCED SNOW MELT. OF COURSE, THE
EXACT POSITION OF THE LOW IS STILL HIGHLY UNCERTAIN AND NEEDS TO
BE MONITORED.
JKL
AVIATION
06Z DISCUSSION...OVERALL VFR CONDITIONS WILL PREVAIL OVER THE
NEXT 24 HOURS. WINDS WILL BE GENERALLY LIGHT AND VARIABLE
OVERNIGHT, BECOMING WESTERLY IN THE AFTERNOON BUT REMAINING BELOW
15KTS FOR MOST LOCATIONS. A FEW WEAK DISTURBANCES COMBINED WITH
RESIDUAL MOISTURE FROM RECENT PRECIPITATION WILL KEEP VERY
ISOLATED SHOWERS IN THE FORECAST, BUT PROBABILITIES ARE TOO LOW TO
MENTION IN THE CURRENT TAFS. FOG PROBABILITIES CONTINUE TO EXIST
RIGHT ALONG THE MT/DAKOTAS LINE INCLUDING KBHK, BUT PROBABILITIES
ARE UNDER 40 PERCENT FOR IFR OR LOWER VISIBILITY. ANY FOG THAT
DOES DEVELOP SHOULD DISSIPATE BY 15Z. CHAMBERS
PRELIMINARY POINT TEMP/POPS
TDY SUN MON TUE WED THU FRI
-------------------------------------------------------
BIL 077 049/086 055/090 058/092 057/079 054/080 055/082
0/U 10/U 00/U 12/T 65/T 62/T 33/T
LVM 074 044/082 049/086 052/084 047/070 046/073 047/076
1/U 10/B 02/T 25/T 78/T 66/T 46/T
HDN 077 045/085 050/092 055/093 056/081 053/081 054/083
1/U 00/B 00/U 01/B 34/T 53/W 33/T
MLS 076 047/086 052/092 061/095 063/086 057/082 057/083
0/U 00/B 00/U 00/N 13/T 33/W 33/T
4BQ 075 047/085 050/091 060/093 062/084 056/080 055/081
2/W 00/B 00/U 00/U 14/T 34/T 33/T
BHK 073 045/085 050/092 057/093 061/085 056/080 054/080
1/U 00/B 00/U 00/N 12/T 33/W 32/T
SHR 073 040/083 044/088 048/089 049/078 047/078 047/080
2/W 00/U 01/U 02/T 27/T 55/T 45/T
BYZ WATCHES/WARNINGS/ADVISORIES
MT...NONE.
WY...NONE.
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